Thread: sbc running rough

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what i mean was they are closed when it is on the 0* mark..sorry..but were the mark is when it is running the valve would be open some.
I know there is no offset key in there..

Do you think it is cuz its too rich??
Maybe need some hotter plugs.

I just don't want to pull the front cover off.I don't feel like pulling apart the whole front of the motor apart..Its not easy being in a s-10 blazer you kow..

When you cleaned the plugs what did they look like black white gray???

black dry carbon

That sounds rich OR sucking oil from somewhere. maybe PCV stuck?? Did you use a sealer when you set the intake??

i used sealer on the ends of the intake.and i have no pcv.
i know it burn a little bit of oil but not that mush in all the cly's

ok i figrure out the timming mark thing.me being dumb on that part.the idle was way up.but it did not same like it was.but still runing bad rough idle and fall's on its face when open the thottle quick..I had to stop for the night do to the noise and being smoked out of the garage..I did change the plugs to a stock range and size.not easy.

Just a thought... maybe idle circuit too rich (fouled plugs lots of advance at idle) but main circuit/transfer slot too lean (knock and bog)? You mentioned you're running the smallest jets you could find. I'm not an expert but maybe an approach like:

1) set timing to ~8-10* at idle (should be ~35* all in ~2500 rpm)
2) adjust idle mix and idle speed for max vacuum at xxx rpm (800?)
3) start increasing main/secondary jet size until it runs right

maybe have a stuck power valve?

As I said, I'm not an expert so take this with a grain of salt and maybe better suggestions....

Good luck,

Chris

If the carb set on the shelf for two years with any amount of gas in it, I'd say you need to rebuild it. The metering block is probably full of varnish.

well i did clean the carb when i put it on the truck.
i got it running the best sofar today but still no powerwill taking off from the stop sign...The timimng mark on the blance must be off becuz the it is still at like 30-60 deg...i get it any were close to were it should be it will not run.
i just change the carb to a 390 cfm 4bbl and still to rich..Maybe i have a bad cly..I not able to check the compresson in the back 4 cly becuz of the headers being in the way.i think i need to find a way check them..pull the header or some thing...

Well i think i will start the tear down tonite.Pull the whole front so i can see the chain and pull the headers to check the cly's..and i will try to find a way to check the blancer and go from there

Hope your inside its going to get WINTER out

yes i am..just need some gas and good to go

ok i have compression test all cly's and they are 120-135psi.The chain is dead on.
The eninge is still runing rich on all cly's.
Still the timming mark is around 40-50* btdc with no vac to the dis..????

You said you changed the damper. Are you aware there is more than one damper for sbc that have the timing mark in different locations.

yes i found that out a while ago..I think i have the one that came with the motor and they lined up in the same spot..I'm going to pull the intake off and check the gasket.Some one left me a comment that the gasket could not be sealing on the bottom side.but it said about it runing lean but i should check it anyways.

will i do not know what i did but it stop running so rich..I readjust all the valves and rebuild the carb and it was running great then the oil pump die.
So now i need a new engine.